HKers urged to stay indoors amid 'unexpected' air pollutants rise

Hong Kong has seen an “unexpected” rise in air pollutants such as ozone and nitrogen dioxide, a meteorologist advises staying indoors unless necessary.

Hong Kong Meteorological Society spokesman Leung Wing-mo stated on a radio program on Monday that the city has recently faced severe sandy weather and air pollution, with Environmental Protection Department data showing changes in the timing of certain pollutants.

Leung noted that Hong Kong last experienced such a severe sandstorm in 2010, describing it as uncommon. He suggested that the sandstorm could originate from the Gobi Desert and Mongolia, where rapid livestock farming has increased desertification.

He explained that a high-pressure ridge near Hong Kong, along with a low-pressure area in Southern China, creates a temperate cyclone. When the cyclone combines with northerly winds, it generates enough force to blow sand and dust into Hong Kong.

Besides, Leung noted that the types of air pollutants have varied recently, with ozone being the main component on Sunday and dust particles on Monday. 

He added that the city’s nitrogen dioxide levels have been high, likely due to northerly winds carrying emissions from daytime vehicles in the mainland.

While masks can block some atmospheric particulate matter, Leung noted they cannot filter out ozone and nitrogen dioxide. He advised that it’s best to stay indoors unless necessary.

He stated that atmospheric particulate matter may not significantly impact short-term health for those in good health, but there are concerns about long-term effects as these particulates can enter and stay in the lungs.

(Cheng Wong)